This Fairchild Semiconductor datasheet covers the KST42 and KST43 high voltage NPN epitaxial silicon transistors, supplied in the SOT-23 package with the pinout 1. Base, 2. Emitter, 3. Collector. Absolute maximum ratings and electrical characteristics are given for both types at a 25 °C ambient/junction temperature unless otherwise noted; the KST42 is rated for 300 V collector-base and collector-emitter voltage and the KST43 for 200 V.
The document also lists marking codes (1D for the KST42, 1E for the KST43), typical characteristic curves for DC current gain, saturation voltage, capacitance and gain bandwidth product, and SOT-23 package dimensions in millimeters. The last page carries Fairchild trademark, disclaimer, life support policy and product status definitions.
| Collector Current | 500 mA |
|---|---|
| Collector Power Dissipation | 350 mW |
| Emitter-Base Voltage | 6 V |
| Storage Temperature | 150 °C |
| Thermal Resistance junction to Ambient | 357 °C/W |
| Collector-Emitter Voltage, KST42 | 300 V |
| Collector-Emitter Voltage, KST43 | 200 V |
| DC Current Gain (VCE=10V, IC=1mA) | 25 min |
| Collector-Emitter Saturation Voltage | 0.5 V max (IC=20mA, IB=2mA) |
| Current Gain Bandwidth Product | 50 MHz |
| Output Capacitance, KST42 | 3 pF |
| Output Capacitance, KST43 | 4 pF |
The collector current rating is 500 mA, with a collector power dissipation of 350 mW.
They are supplied in the SOT-23 package with pinout 1. Base, 2. Emitter, 3. Collector.
The KST42 is marked 1D and the KST43 is marked 1E.
The KST42 collector-emitter breakdown voltage is 300 V, while the KST43 is rated 200 V.